Location: Foreign Arthropod Borne Animal Disease Research
Project Number: 3022-32000-024-019-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Aug 15, 2024
End Date: Aug 14, 2025
Objective:
Understanding and predicting disease epidemiology relies on organismal knowledge and at the core of this knowledge is differentiating species. Cryptic and sibling species are difficult to distinguish because they look morphologically similar but may have very different vector competence (ability to transmit virus). Other Culex and Aedes genera mosquito species are implicated as potential secondary vectors for virus transmission as well. Therefore, to identify the role of each mosquito species in arbovirus transmission dynamics and the mechanistic work at the vector-pathogen interface, molecular and morphological markers must be identified to differentiate species. The objective of this project is: (1) Understand the taxonomic status of the vector species within the aedine subgenus Neomelaniconion; (2) Assess the Rift Valley fever virus mosquito vector diversity in South Africa; (3) Determine the extent to which the phylogeographic structure of these vectors are associated with the occurrence of RVF; and, (4) to investigate short-term (intra-annual) and long-term (inter-annual) temporal variation in genetic diversity of the RVFV vectors.
Approach:
To identify species specific markers and to assess the genetic structure of mosquitoes, the Cooperator team conducted regular entomological surveillance targeting potential Rift valley fever virus mosquito vectors throughout South Africa with a focus in the KwaZulu-Natal province for almost 8 years. Some of the historical collections have been morphologically identified and stored at -20°C for future work, while the majority is frozen but remains unidentified to species. The frozen mosquitoes are the baseline of this project, although additional collections will be done to increase the specimen numbers of specific species using carbon dioxide baited traps (CDC miniature and tent traps). Collected mosquitoes and biting flies will be immediately euthanized, and transported to the Cooperator facility where they were stored frozen until identified to species. The small biting flies, while not part of this project, will also be stored in 95% ethanol and frozen for future projects.
